Mobile devices are becoming a new target for spam and malware attacks as the volume of spam emails begin to decrease, according to new information from Kaspersky Lab.

The latest Kaspersky Lab Security Bulletin says the volume of spam emails in 2015 decreased to 55.28% of overall email traffic – a fall of 11.48% on the previous year.

According to the company, the significant slump in spam emails can be attributed to the increasing popularity of legal advertising platforms on social networks and coupon clipping services.

Spam goes mobile

In 2015 cybercriminals continued to send out fake emails from mobile devices and notifications from mobile apps containing malware or advertising messages, Kaspersky Lab explains.

New tactics included fraudsters  spreading malware in the form of .apk (Android executive files) and .jar (ZIP archives containing a program in Java).

In addition, cybercriminals masked a mobile encryption trojan behind a file containing updates for Flash Player. After launching, the malware encrypted images, documents and video files stored on the device with users receiving a message telling them to pay a fee in order to the decrypt files.

“The increased use of mobile devices in our everyday life to exchange messages and data, as well as access and control bank accounts, has also resulted in increased exploitation opportunities for cybercriminals,” explains Daria Loseva, spam analysis expert at Kaspersky Lab says.

“Mobile malware and fraudulent spam is becoming more popular and efforts to dupe victims are becoming more sophisticated year on year, with the emergence of apps that can be used by cybercriminals both directly (for sending out spam, including malicious spam) and indirectly (via phishing emails),” she says.

“Mobile device users therefore need to be on their guard and remain vigilant, as cybercriminal activities in this area are only likely to increase, along with our reliance on devices,” says Loseva.

The Kaspersky Lab spam report also identified the following trends in 2015:

• Over three quarters (79%) of all emails sent were less than 2kb, which shows a steady decrease in email size for spam campaigns over the past few years.
• The US remained the biggest source of spam (15.2%), with second place taken by Russia (6.15%) and China making way for Vietnam in third spot (6.12%).
• Financial institutions such as banks, payment systems and online shops were attacked most often with phishing emails (34.33%, a rise of 5.59%)

Hot spam topics of the year

Although the Olympic games in Brazil has yet to take place, fraudsters have already started to exploit the event, sending emails announcing false lottery wins and asking the recipient to fill in a form with their personal details.

In these attacks, emails with pdf attachments, pictures and other graphical elements were designed to fool the spam filters.

‘Nigerian' fraud used the Ukrainian political situation, the Syrian civil war, the election in Nigeria and the earthquake in Nepal to exploit the kindness and empathy of recipients with believable email content. These emails contained content calling for material support for a person in need.